The present invention relates to a seal structure for achieving waterproofing of a waterproof connector or the like.
FIG. 6 shows a related waterproof connector 100 described in JP-A-2009-48929. A terminal accommodation chamber 113 is formed in a housing 110 of the waterproof connector 100. A rubber plug attachment cavity 115 communicates with the terminal accommodation chamber 113 at an electric wire drawing side thereof (a rear side). A terminal metal fitting 125 coupled to an electric wire 120 is inserted into the terminal accommodation chamber 113. A rubber plug 130 and a pressing member 140 are inserted into the rubber plug attachment cavity 115.
The rubber plug 130 is formed of a silicon resin or the like and the outer diameter of the rubber plug 130 is larger than the rubber plug attachment cavity 115. The rubber plug 130 is inserted into the rubber plug attachment cavity 115 in a compressed state. An electric wire insertion hole 135 into which an electric wire 120 is to be inserted is formed on the rubber plug 130.
The pressing member 140 is formed of an insulation resin formed in a block shape and is to be inserted into the rubber plug attachment cavity 115 from a rear side of the rubber plug 130. An electric wire insertion hole 145 communicating with the electric wire insertion hole 135 of the rubber plug 130 is formed on the pressing member 140.
In the waterproof connector 100, a plurality of engagement recessed portions 117 forming a sawtooth configuration are formed on an inner face of the rubber plug attachment cavity 115 at an inlet part. An engagement projection portion 147 to be engaged with any one of the engagement recessed portions 117 is formed on an outer face of the pressing member 140.
In the waterproof connector 100, the electric wire 120 is inserted into the electric wire insertion hole 145 of the pressing member 140 and the electric wire insertion hole 135 of the rubber plug 130. Under the above condition, the terminal metal fitting 125 is inserted into the terminal accommodation chamber 113 and the rubber plug 130 is inserted into the rubber plug attachment cavity 115. After that, the pressing member 140 is inserted into the rubber plug attachment cavity 115 from the rear side of the rubber plug 130 so as to press the rubber plug 130, thereby engaging the engagement projection portion 147 with one of the engagement recessed portion 117 of the rubber plug attachment cavity 115. By the engagement, the rubber plug 130 and the pressing member 140 are fixed to the housing 110.
With the above configuration, since the rubber plug 130 is compressed by the pressing of the pressing member 140, an outer face of the rubber plug 130 is brought into intimate contact with the inner face of the rubber plug attachment cavity 115 as well as the electric wire insertion hole 135 is brought into intimate contact with an outer face of the electric wire 120. Accordingly, the electric wire 120 can be held in a waterproof state.
In the waterproof connector 100 shown in FIG. 6, when an electric wire 120 having a small outer diameter (a thin electric wire) is attached, the pressing member 140 is further pushed thereinto along a longitudinal direction of the electric wire 120 and the engagement projection portion 147 is engaged with the engagement recessed portion 117 at the front side. Accordingly, since the diameter of the electric wire insertion hole 135 of the rubber plug 130 is further reduced, the rubber plug 130 can be brought into intimate contact with the thin electric wire 120. Therefore, even when diameters of the electric wires 120 are different from each other, the electric wires can be attached to the housing 110.
However, in the above related waterproof connector 100, it is necessary to adjust a pushing amount of the pressing member 140 depending on each of the electric wires having the different diameters. Therefore, a work for attaching of a plurality of electric wires having different diameters has been troublesome.
In the above circumstances, a mat seal capable of achieving integral waterproofing of electric wires having different diameters has been developed in recent years. The mat seal has a body made of insulation resin and a plurality of electric wire insertion holes formed in the body. The body has a block plate shape.
The body of the mat seal is fitted into an attachment cavity of a housing so as to be in intimate contact with an inner face of the attachment cavity. A lip portion is provided at the inner face of each of the electric wire insertion holes in the mat seal so as to be projected in a wave shape. A projection amount of the lip portion in each of the electric wire insertion holes is set so as to be matched with the diameter of the electric wire to be inserted thereinto. Accordingly, the inner face of each of the electric wire insertion hole can be in intimate contact with the electric wire. In the above described mat seal, since each of the electric wire insertion holes (the lip portion) is in intimate contact with the outer face of the electric wire by inserting the electric wire into the electric wire insertion hole whose diameter is matched with the diameter of the electric wire, it is possible to allow the mat seal to have a structure achieving waterproofing without attachment of a rubber plug even when the electric wires have different diameters. For this reason, it is possible to achieve integral waterproofing.
However, in the mat seal, it is necessary to change the projection amounts (the inner diameters of the electric wire insertion holes) of the lip portions of the electric wire insertion holes so as to be matched with the diameters of the electric wires so as to form electric wire insertion holes having different inner diameters on the mat seal. Therefore, in a case where a number of circuit patterns is increased and a number of kinds of the diameters of the electric wires is increased, it is necessary to prepare many kinds of (part numbers) of the mat seals so that problems arise that selecting of the mat seal is complicated or troublesome, and thereby, the cost is increased.